The present invention generally pertains to power tools. More particular, the present invention pertains to a system of cordless power tools. More specifically, but without restriction to the particular embodiment and/or use which is shown and described for purposes of illustration, the present invention relates to a system of cordless power tools with an improved battery pack interface. The present invention also pertains to a related method.
Cord less power tools including interchangeable battery units are widely known in the prior art. For example, one such system is shown and described in commonly assigned U.S. Pat. No. 3,952,239. U.S. Pat. No. 3,952,239 discloses a system of tools utilizing individual tool heads, each of which incorporates its own essential elements such as a motor and a blade or chuck. This type of system reduces space requirements for tool storage and increases the life span for each motor. Another significant aspect of systems such as that disclosed by U.S. Pat. No. 3,952,239 is the fact that they permit improved utilization of incorporated nickel-cadmium batteries and an associated battery charger which are particularly high cost elements of the system.
While prior art systems, including but not limited to the type disclosed in U.S. Pat. No. 3,952,239, have proven to be suitable for many intended uses, they are all associated with certain disadvantages and/or limitations.
It is a general object of the present invention to provide an improved system of cordless power tools.
It is another object of the present invention to provide a battery pack for a cordless power tool with first and second housing halves and defining upper and lower chambers. A battery may be located in the lower chamber and a battery pack terminal block may be located in the upper chamber.
It is a related object of the present invention to provide a battery pack for a cordless power tool having longitudinally extending guide rails for engaging the tool and longitudinally extending terminal blades located between the rails. The front tips of the terminal blades and the guide rails have transversely aligned front tips. It is another object of the present invention to provide a battery pack for a cordless power tool having a housing defining an upper chamber receiving a terminal block. The terminal block includes a plurality of pack terminals which are perpendicular to and spaced above a floor of the upper chamber thereby providing improved clearance around the terminals and also reducing the potential for contamination of the terminals with debris.
It is another object of the present invention to provide a method of releasably and electrically interconnecting a battery pack with a tool terminal block of a cordless power tool. The battery pack is first roughly centered along a longitudinal axis of the tool handle through engagement of guide rails with the cooperating rails carried by the tool. Then the battery pack is finely centered through engagement of battery pack terminals through engagement of the tool terminal block with the battery pack.
It is another object of the present invention to provide a battery pack for a cordless power tool which includes suitable protrusions to facilitate manual extraction.
It is another object of the present invention to provide a system of cordless power tools including a rechargeable battery pack, a non-isolated AC/DC converter having recessed terminals for interfacing with the tool and a non-isolated charger having recessed terminals for interfacing with the battery pack.
It is another object of the present invention to provide a system of cordless power tools including a charger having a housing with an open recessed deck for vertically receiving a rechargeable battery pack and a coupling portion for mechanically aligning the battery pack and the charger terminals and also connecting the battery pack mechanically in the charger such that longitudinal translation of the battery pack toward the coupling portion prevents vertical displacement of the battery pack relative to the housing.